Method of preserving the inner walls of furnaces.



BEST AVAILABLE COF" PATENTED EEB. 13, 1906.

P. C. W. TIMM.

METHOD OE PRESERVING THE INNER WALLS 0F EURNAGES.

APPLICATION FILED Amm, 1905.

I l I l l I MMJJITT,

ym/IQ BEST AVAILABLE COF" UNITED 4snrarns ieAnNT onirica.

FRIEDRICH CARL l/VILHELM TIMM, OFfIAMBURG, GERMANY.

METHOD OF PRESERVING THE INNER WALLS OF FURNACES..

Specification of Letters Patent.

Patented Feb. 13, 1906.

Application led April 2l, 1905. Serial No. 256,823. 4

i ing treated which in a soft or molten state l. eat into anddisintegrate the lining. In

many cases the cooling is applied from outside in the shape ofWaterjackets or by spraying, to ether with a specially thick structureof ining. The mean temperature f the lining is lowered by the cooling,and its mechanical solidityis thereby increased, and

`by. lessening the pores the ldisintegration is made difficult.

These methods are, however, frequently insufficient, and the idea ofapplying the method of continuously-working or perpetual furnaces hadtherefore to be abandoned notwithstanding that otherwise in manyprocesses everything was favorable.

The present method allows of the furnace bein worked uninterruptedlyunder the most :30

di ficult conditions and witha perfect preservation of the inner lining,it being at the same time avoided that the mass be made impure bydisinte rated lining.

. The method wil be understood by reference to the accompanyingdrawings, in which- Figure l is a vertical cross-section. Fig. 2

is a horizontal section on line a l) of Fig. l.

A is the shaft of the furnace of iireproof material and which isinclosed in a casing B of metal. The material to be burned or smeltedand the combustible substance (coke) are filled into the shaft fromabove. The air for combustion is fed through the nozzle C. Underneaththe latter collects the melted or softened material, which is coveredexteriorly with a crust and by continuous cooling gradually hardens orsets in the under part of the shaft. In this condition the block offinished material appears before the openings D. Through these openingsspindles S are from time to time inserted by means of hand-wheels T andwhich s indles :'.rmly hold the block` with the rest of t e connts ofthel furnace over same above D. reupon the ram F is lowered and theunder u of th e block is removed through the doors l G, the ram F beingthen again pressed against the block and the spindles drawn back.

After closing the doors G the ram F is given a p slow downward movementcorresponding to the extent necessitated by the continuous burningprocess before the twyers. YThe movement of the rain`can be effectedhydraulically or by racks, screws, or the like, and the spindles S,serving for holding the contents of the furnace, can be replaced by,`

any other suitable device.

The peculiarity of the present method consists in the melted contents ofthe furnace bef ingalowe iningwith In order to efthe re r o rnace-wallfec s, an inc osure of bricks 1s arranged i between the walls A and thering J, held the brackets IJ. The manner of carrying this p formation tobe 25 by 12 by 6.5 centimeters,.fv 34- 1 a ring of twelve centimetersheight is fitted-l..

out is as follows: Supposing the known stone against. the furnace-walls.Stone on stone is then laid round same, each one of which contacts withthe wall A on a surface oftwelve centimeters height and twenty-fivecentimeters length circumferential measurement. Against this ring thecharge is thrown into the interior4 in such quantities .that thecontents of the furnaces lies flush with the upper edge of the' ring,the said contents having beenthus raised twelve centimeters. Thereuponanother ring of twelve centimeters height isbuilt on the previous one,and the furnace is again charged as before, the same thing beingcontinued uninterruptedly or with intervals, according as to the levelof the contents of the furnace being lowered by the working of the fire.i

In this way the charge arrives at the twyers without having come intocontact with the walls A over same. their totality an inner protectivecasing E, which keeps the contents of the furnace separated from thelining proper. This perfect cover is, however, partly destroyed before.

the twyers C by inserting hand or machine tools through the latter,making holes in the casing E, through which the air can have access tothe charge. Seeing the casing E is constantly moving downward and thetools are constantly making holes in same, it will be The single ringsform in ICO clear that the said casing must have slits` underneath thelevel of the twyers and running parallel to its axis. that no injuriouscontact of the fluid or softhrough these slits, cooling-boxes H are ar`In order, however,-y

mf Y

i 1o4 tened mass can-take place with the wall A A BEST AvAiLABLE coPprogress of the fire can be observed and the lowering of the finishedcontents in the lower.

part of the furnace, as also the charging from the'mouth of same can beregulated accordingly, as previously described.

In order to extract the waste gases, ataking-o apparatus is arranged,the construction of which, having regard to the construction of thecasing E, differs from the apparatus usually used in blast-furnaces. A`cylindrical rin J is secured to the fur-nace or the .top plat orm bymeans of several brackets L. Several rods I), supported onthe brackets,carry' the carrying-0H pipe Q `for the wastegases.v The charge, in theforni of se arate layers or mixed, is thrown to thetop be l' apparatus Mand guided byalternately raising and lowering same, as also thebellfaplparatus'N by means of the chains R in the interior ofthe furnacein the samemanner as in any other takin -off apparatus. The chains R,secured to t e bells, lead to levers (not shown) which eect the raisingor. lowering in the usual way. The distance between the ring J and thecasing E is the saine as the thickness of the rotective casing, Thestonesformi'ng the atter are constantly set on each-other, so, thatl thelining is perfectlclosed up to about the level ofthe nouth. f the casingis then lowered fora certain distance, owing to the working of thefurnace, a new layer is added. In thisl way the part of the casingbehindthe ring T prevents the escape' 4of gas.

l As regards the nature of the stones used for forming the rotectivelining it maybe mentioned that t ey can consist of the known iireproofmaterials of a suitable consistency for the particular purpose orwerialof the charge itself; The atter can be use w en solidiied' or when itisdesired that there shouldl be an entire ab,- sence of foreign bodies.Where itis a uestion, for instance, of the production of si 'cid of ironof high percentage, it is advantageous t'o use bri uets out of'easily-reducibl es with strong silicious additions and with powderedcoke. The ore briquets and heatingco e are led in the interior of theprotective casing, while the latter likewise consistl of ore briquets.

The protective casing enables the use of l blasts rich in oxygen,whereby a silicid of iron of high 'percentage is obtained, while withoutthe casing the Wear of the fireproof inner lining would be too great,owing to the high'temperature and acid sla For this reason silicid' ofiron of the higher percentages is even today obtained by electric-namearcs.

It is not necessary that the protective castwr.

ing should be made of stones of finished form.

It might be preferable to insert an annular metal templet or ring in thefurnace and to fill the charge inside same, while the intermediate spacebetween teinplet or ring and inner lining A isl filled up by stamping-asuitable material in saine. For example, said material may be of thesanie character from which the lining-bricks are formed, and in this waya protective case E is likewise ob# tained.

For the proper working with the casing it is important to gage itsthickness correctly. The essence of the casing lies in its acting as apart lof the inner lining A, or, in other words, that the furnace isabout the same as another one for a shorter working duration would bewith a lining of a thickness of A plusE.

Every lining wears away to suoli extent that the upper surface, which isexposed to the iire and the chemical action, softens up to a givendepth. Thisl layery is then removed either by mechanicall frictionduring the de.- scent ofthe charge or by meltin away orby thesimultaneous action of both actors.- For thisV reason places become softwhich were previously suficiently solid when they lay sufficiently deepunder thel surface. Such a place exists where the lining A and theprotective casing E come in contact.

The protective casing is-attached on the in sidel during its movementthrough the. furnace. Its thickness must, however, besufiicient toprevent any combining with the lining A.- The correct thickness of theprotective casing is therefore essential for the proper working of theprocess, sincewhere the casing-is too weak'there is a danger of apartial fusing of same with the walliA, while in the case of a too-thickcasing too great a mass moves unnecessarily through the fire.

TOO

The use ofl the casing makes it possible to I IIO rials-not corrosive,when the usual method of lining is used ,'-but by letting a protectivecasing of a thickness corresponding to the temerature and the chemicalaction pass through the furnace the casing is subject to wear, but thelining A proper is preserved.

It is by no means always necessary to provide the furnace with a wall Aof iireproof stones. Instead of this under certain circumstances theusual water-jacket may be used with advantage. The process is thenpresent when the material is drawn off from the furnace in a fluidinstead of a solid state. There is then no solid connection of thecasing underneath the twyers with the content of the furnace, and thecasing can pf through the furnace-at a less speed than t BEST AVAILABLECOF" the casing is usually clamped in the under part of the furnace andis then treated in regard to the charges in the same way as the ordinaryimmovable lining of the furnace. From time to time, however, the casingis allowed to descend with the contents of the furnace, it being thenagain fastened and the charge delivered and tapped the same as in knownfurnaces. The piercing of the casing before the twyers takes placeexactly as above described. In this modification of the process thecasing preferably receives a greater thickness, which disappears in thefire zone gradually to a permissible degree, whereupon the protectivecasing is moved downward.

For the method of workin as explained coke is assumed to be the comustible material with the charge; but this can in many cases be deviatedfrom and combustible material in the form of powdered coal-dust,gaseous, or sprayed fluid combustible material can be used. The natureof the combustible material is not essential for the rocess, since it isonly a question of the com ustion being effected within the furnace.

The protective casin used in the present process differs essential yfrom a protective coating applied to a cement furnace notwithstandingthat a certain exterior similarity exists. Thewalls ofperiodically-driven cement furnaces are smeared with mud or slime beforecharging or a protective lining may be laced in cylindrical furnace's ofunbaked ,'ricks for Iortland-cement in a similar way to what is abovedescribed, the charge consisting of unbaked bricks and coke. Suchfurnaces are about twelve meters high' and are so built that the firezone lies 1.2 to two meters from the top, so that the cooling oif of theburned clinkers takes place at a height of 10.8 to ten meters. Below atthe drawingoff o ening for the cold clinkers the air for com ustionenters and rises vertically, thus cooling the contents and heatingitself and burns the coke in the fire zone.

The necessity of drawing solid masses out of the furnace, the longcooling-chamber,

the vertical manner of feeding the air in the zone of combustion, andthe impossibility of handling such materials which are attacked '5oI ina fluid or pasty state (underneath the iire Zone) by the oxygen of thecombustible air represents the difference between the method for cementfurnaces and the present process.

In order to increase the protective action 5 5. of the lining, it mayconsist of a material which decomposes in heat under absorption of thelatter. In this way a greater reduction of temperature from inside tooutside is obtained. As an example ofthis modification suppose thefurnace process lays it down that lime must form a part of theprotectivev agent. If, then, this is chosen in the form of carbonate oflime, the heat necessary for driving out the carbonio acid formsan-addi- 6 5 tional protection with regard to the liningconsisting ofburnt lime.

Having thus declared the nature of my,` said invention and in whatmanner it is to be performed, I declare that What I claim'is- 7o 1. Amethod of preserving inner Walls of shaft-furnaces, which consists inbuilding up against the inner Wall of said furnace during the chargethereof, a gravity-movable casing, and then piercing said casing infront of the twyers as the said casing lowers so that means to sustaincombustion can pass through the openings into the interior of thecasing.

2 A method of preserving inner walls of A shaft-furnaces which consistsin building up 8o against the inner wall of the furnace during thecharge thereof, a gravity-movable lining, piercing said lining as thesaid lining lowers so that means to sustain combustion can pass, intothe interior of the furnace and adding to the lining at the top thereofwhen the lining lowers.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

FRIEDRICH CARL WILHELM TIMM.

Witnesses:

ERNEST H. L. MUMMENHOFF, O'rTo W. HELLMRICH.

